vt.

包嚢に包む

active infection in the immunocompromised host is most likely to be due to the spontaneous release of encysted parasites that undergo rapid transformation into tachyzoites within the CNS.(HIM.1305)(免疫不全宿主における活動性の感染は中枢神経内の急増虫体への急激な転換を経た嚢胞寄生虫の自発的な放出によるとするのがもっともらしい)

vi.

包嚢に包まれる

WordNet

pass through; "The chemical undergoes a sudden change"; "The fluid undergoes shear"; "undergo a strange sensation"
enclosed in (or as if in) a cyst

PrepTutorEJDIC

…‘を'包嚢(ほうのう)に包む / 包嚢(ほうのう)に包まれる
〈変化・検査など〉‘を'『受ける』,経験する(experience) / 〈困難など〉‘に'耐える,あう

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/12/12 02:52:23」(JST)

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Cyst stage of Entamoeba histolytica

Cyst of Artemia salina

A microbial cyst is a resting or dormant stage of a microorganism, usually a bacterium or a protist or rarely an invertebrate animal, that helps the organism to survive in unfavorable environmental conditions. It can be thought of as a state of suspended animation in which the metabolic processes of the cell are slowed down and the cell ceases all activities like feeding and locomotion. Encystment also helps the microbe to disperse easily, from one host to another or to a more favorable environment. When the encysted microbe reaches an environment favorable to its growth and survival, the cyst wall breaks down by a process known as excystation.

Unfavorable environmental conditions such as lack of nutrients or oxygen, extreme temperatures, lack of moisture and presence of toxic chemicals, which are not conducive for the growth of the microbe^[1] trigger the formation of a cyst.

Cyst formation across species

In bacteria

In bacteria (for instance, Azotobacter sp.), encystment occurs by changes in the cell wall; the cytoplasm contracts and the cell wall thickens. Bacterial cysts differ from endospores in the way they are formed and also the degree of resistance to unfavorable conditions. Endospores are much more resistant than cysts.

In protists

Protists, especially protozoan parasites, are often exposed to very harsh conditions at various stages in their life cycle. For example, Entamoeba histolytica, a common intestinal parasite that causes dysentery, has to endure the highly acidic environment of the stomach before it reaches the intestine and various unpredictable conditions like desiccation and lack of nutrients while it is outside the host.^[2] An encysted form is well suited to survive such extreme conditions, although protozoan cysts are less resistant to adverse conditions compared to bacterial cysts.^[1] In addition to survival, the chemical composition of certain protozoan cyst walls may play a role in their dispersal. The sialyl groups present in the cyst wall of Entamoeba histolytica confer a net negative charge to the cyst which prevents its attachment to the intestinal wall^[3] thus causing its elimination in the feces. Other protozoan intestinal parasites like Giardia lamblia and Cryptosporidium also produce cysts as part of their life cycle (see oocyst). In some protozoans, the unicellular organism multiplies during or after encystment and releases multiple trophozoites upon excystation.^[2]

In nematodes

Some soil-dwelling plant parasitic nematodes, such as the soybean cyst nematode, or the potato cyst nematode form cysts as a normal part of their lifecycle.

Composition of the cyst wall

The composition of the cyst wall is variable in different organisms. The cyst walls of bacteria are formed by the thickening of the normal cell wall with added peptidoglycan layers whereas the walls of protozoan cysts are made of chitin,^[3] a type of glycoprotein. Nematode cyst walls are composed of chitin reinforced by collagen.

References

^ ^a ^b Eugene W. Nester, Denise G. Anderson, C. Evans Roberts Jr., Nancy N. Pearsall, Martha T. Nester; Microbiology: A Human Perspective, 2004, Fourth Edition, ISBN 0-07-291924-8
^ ^a ^b Samuel Baron MD, Rhonda C. Peake, Deborah A. James, Mardelle Susman, Carol Ann Kennedy, Mary Jo Durson Singleton, Steve Schuenke; Medical Microbiology; Fourth Edition, ISBN 0-9631172-1-1 (hardcover)1996
^ ^a ^b Anuradha Guha-Niyogi, Deborah R. Sullivan and Salvatore J. Turco; Glycoconjugate structures of parasitic protozoa; Glycobiology, 2001, Vol. 11, No. 4 45R-59R

UpToDate Contents

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1. 腸管寄生虫症 intestinal flukes
2. 旋毛虫症 trichinellosis
3. トキソカラ症：内臓および眼幼虫移行症 toxocariasis visceral and ocular larva migrans
4. 免疫宿主におけるトキソプラズマ症 toxoplasmosis in immunocompetent hosts
5. 肺吸虫症 paragonimiasis

English Journal

Redescription and life cycle of the monorchiid Postmonorcheides maclovini Szidat, 1950 (Digenea) from the Southwestern Atlantic Ocean: Morphological and molecular data.

Bagnato E1, Gilardoni C2, Pina S3, Rodrigues P4, Cremonte F5.
Parasitology international.Parasitol Int.2016 Feb;65(1):44-9. doi: 10.1016/j.parint.2015.09.008. Epub 2015 Sep 28.
The adult monorchiid, Postmonorcheides maclovini Szidat, 1950, digenean parasite of the Patagonian blennie Eleginops maclovinus (Cuvier) (Eleginopidae) from Puerto Deseado (47° 45' S, 65° 55' W), Argentina, was characterized and its life cycle elucidated. P. maclovinus is the only species of the g
PMID 26423199

MSCs: The Sentinel and Safe-Guards of Injury.

Caplan AI1.
Journal of cellular physiology.J Cell Physiol.2015 Nov 13. doi: 10.1002/jcp.25255. [Epub ahead of print]
Mesenchymal Stem Cells (MSCs) were originally named because they could differentiate in a variety of mesenchymal phenotypes in culture. Evidence indicates that MSCs arise from perivascular cells, pericytes, when the blood vessels are broken or inflamed. These pericyte/MSCs are situated on every bloo
PMID 26565391

The life cycle of Hexangium sigani Goto & Ozaki, 1929 (Digenea: Microscaphidiidae) from the Red Sea.

Hassanine RM1, Al-Zahrani DA1, Touliabah HE1, Youssef EM2.
Journal of helminthology.J Helminthol.2015 Aug 17:1-8. [Epub ahead of print]
The microscaphidiid Hexangium sigani Goto & Ozaki, 1929 was found in the intestine of Siganus rivulatus, a siganid fish permanently resident in a lagoon within the mangrove swamps on the Egyptian coast of the Gulf of Aqaba. Intra-molluscan stages of this trematode (mother sporocysts, rediae and
PMID 26279005

Ecology of free-living metacercariae (Trematoda).

Morley NJ1.
Advances in parasitology.Adv Parasitol.2015 Jun;89:1-78. doi: 10.1016/bs.apar.2015.03.004. Epub 2015 Apr 28.
The presence of trematodes with a free-living metacercarial stage is a common feature of most habitats and includes important species such as Fasciola hepatica, Parorchis acanthus and Zygocotyle lunata. These trematodes encyst on the surface of an animal or plant that can act as a transport host, wh
PMID 26003035

Japanese Journal

Emergence of the Terrestrial Ciliate Colpoda cucullus from a Resting Cyst : Rupture of the Cyst Wall by Active Expansion of an Excystment Vacuole

FUNADANI RYOJI,SUETOMO YASUTAKA,MATSUOKA TATSUOMI
Microbes and environments 28(1), 149-152, 2013-03-01
… cucullus was induced to encyst in a hypotonic medium containing NaN3, the expansion of the excystment vacuoles was inhibited. …
NAID 10031138556

Massaliatrema misgurni n. sp.(Trematoda: Heterophyidae) whose metacercariae encyst in loaches (Misgurnus anguillicaudatus)

Ohyama Fumio,Okino Tetsuya,Ushirogawa Hiroshi
Parasitology international : official journal of the Japanese Society of Parasitology 50(4), 267-271, 2001-11-01
NAID 10009072221

Chemotaxis of Fungal Zoospores, with Special Reference to Aphanomyces cochlioides

Islam Md.Tofazzal,Tahara Satoshi
Bioscience, biotechnology, and biochemistry 65(9), 1933-1948, 2001-09-23
… The aggregated spores then adhere, encyst, germinate, and finally penetrate into the root tissues to initiate infection. …
NAID 110002693443

Inhibition of Encystation of Entamoeba invadens by Aphidicolin

KUMAGAI Masahiro,MAKIOKA Asao,OHTOMO Hiroshi,KOBAYASHI Seiki,TAKEUCHI Tsutomu
Tokai journal of experimental and clinical medicine 23(6), 313-317, 1998-08-29
… These results suggest that the trophozoites accumulated at G1/S border by treatment with aphidicolin cannot encyst upon induction of encystation so that they need DNA synthesis before encystation. …
NAID 110004700227